Hafnium Element Information, Facts, Properties, Trends, Uses, Comparison with other elements
Hafnium is a chemical element with symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent Transition Metal, hafnium chemically resembles zirconium and is found in zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869, though it was not identified until 1923, making it the penultimate stable element to be discovered (rhenium was identified two years later).
It belongs to group 4 of the periodic table having trivial name null. You can also download Printable Periodic Table of Elements Flashcards for Hafnium in a PDF format.
Hafnium Facts
Read key information and facts about element Hafnium
| Name | Hafnium |
| Atomic Number | 72 |
| Atomic Symbol | Hf |
| Atomic Weight | 178.49 |
| Phase | Solid |
| Color | Gray |
| Appearance | steel gray |
| Classification | Transition Metal |
| Natural Occurance | Primordial |
| Group in Periodic Table | 4 |
| Group Name | titanium family |
| Period in Periodic Table | period 6 |
| Block in Periodic Table | d-block |
| Electronic Configuration | [Xe] 4f14 5d2 6s2 |
| Electronic Shell Structure (Electrons per shell) | 2, 8, 18, 32, 10, 2 |
| Melting Point | 2506 K |
| Boiling Point | 4876 K |
| CAS Number | CAS7440-58-6 |
How to Locate Hafnium on Periodic Table
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 72 to find Hafnium on periodic table.
Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Hafnium on periodic table look for cross section of group 4 and period 6 in the modern periodic table.
Hafnium History
The element Hafnium was discovered by D. Coster and G. von Hevesy in year 1922 in Denmark. Hafnium was first isolated by D. Coster and G. von Hevesy in 1922. Hafnium derived its name from Hafnia, the New Latin name for Copenhagen.
| Discovered By | D. Coster and G. von Hevesy |
| Discovery Date | 1922 in Denmark |
| First Isolation | 1922 |
| Isolated by | D. Coster and G. von Hevesy |
Georges Urbain claimed to have found the element in rare-earth residues, while Vladimir Vernadsky independently found it inorthite. Neither claim was confirmed due toWorld War I, and neither could be confirmed later, as the chemistry they reported does not match that now known for hafnium. After the war, Coster and Hevesy found it by X-ray spectroscopic analysis in Norwegian zircon. Hafnium was the last stable element to be discovered.
Hafnium Uses
Hafnium is a good neutron absorber, so it is used in nuclear control rods in nuclear submarines. Due to its high melting point, it is also used in plasma welding torches. Hafnium oxide is used in microchips
Hafnium Presence: Abundance in Nature and Around Us
The table below shows the abundance of Hafnium in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.
| ppb by weight (1ppb =10^-7 %) | ppb by atoms (1ppb =10^-7 %) | |
|---|---|---|
| Abundance in Universe | 0.7 | 0.005 |
| Abundance in Sun | 1 | 0.01 |
| Abundance in Meteorites | 170 | 20 |
| Abundance in Earth's Crust | 3300 | 380 |
| Abundance in Oceans | 0.008 | 0.00028 |
| Abundance in Humans | - | - |
Crystal Structure of Hafnium
The solid state structure of Hafnium is Simple Hexagonal.
The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.
Unit Cell Parameters
The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)
| a | b | c |
|---|---|---|
| 319.64 pm | 319.64 pm | 505.11 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
| alpha | beta | gamma |
|---|---|---|
| π/2 | π/2 | 2 π/3 |
The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.
The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.
| Space Group Name | P63/mmc |
| Space Group Number | 194 |
| Crystal Structure | Simple Hexagonal |
| Number of atoms per unit cell |
The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.
Hafnium Atomic and Orbital Properties
Hafnium atoms have 72 electrons and the electronic shell structure is [2, 8, 18, 32, 10, 2] with Atomic Term Symbol (Quantum Numbers) 3F2.
| Atomic Number | 72 |
| Number of Electrons (with no charge) | 72 |
| Number of Protons | 72 |
| Mass Number | 178 |
| Number of Neutrons | 106 |
| Shell structure (Electrons per energy level) | 2, 8, 18, 32, 10, 2 |
| Electron Configuration | [Xe] 4f14 5d2 6s2 |
| Valence Electrons | 5d2 6s2 |
| Valence (Valency) | 4 |
| Main Oxidation States | 4 |
| Oxidation States | -2, 0, 1, 2, 3, 4 |
| Atomic Term Symbol (Quantum Numbers) | 3F2 |
Bohr Atomic Model of Hafnium - Electrons per energy level
| n | s | p | d | f |
|---|
Ground State Electronic Configuration of Hafnium - neutral Hafnium atom
Abbreviated electronic configuration of Hafnium
The ground state abbreviated electronic configuration of Neutral Hafnium atom is [Xe] 4f14 5d2 6s2. The portion of Hafnium configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Xe]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. This is important as it is the Valence electrons 5d2 6s2, electrons in the outermost shell that determine the chemical properties of the element.
Unabbreviated electronic configuration of neutral Hafnium
Complete ground state electronic configuration for the Hafnium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d2 6s2
Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.
As per the Aufbau principle the electrons will occupy the orbitals having lower energies before occupying higher energy orbitals. According to this principle, electrons are filled in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…
The Pauli exclusion principle states that a maximum of two electrons, each having opposite spins, can fit in an orbital.
Hund's rule states that every orbital in a given subshell is singly occupied by electrons before a second electron is filled in an orbital.
Atomic Structure of Hafnium
Hafnium atomic radius is 208 pm, while it's covalent radius is 150 pm.
| Atomic Radius Calculated | 208 pm(2.08 Å) |
| Atomic Radius Empirical | 155 pm (1.55 Å) |
| Atomic Volume | 13.44 cm3/mol |
| Covalent Radius | 150 pm (1.5 Å) |
| Van der Waals Radius | - |
| Neutron Cross Section | 104 |
| Neutron Mass Absorption | 0.02 |
Spectral Lines of Hafnium - Atomic Spectrum of Hafnium
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.
Spectral lines are the result of interaction between a quantum system and a single photon. A spectral line may be observed either as an emission line or an absorption line.
Spectral lines are highly atom-specific, and can be used to identify the chemical composition of any medium. Several elements, including helium, thallium, and caesium, were discovered by spectroscopic means. They are widely used to determine the physical conditions of stars and other celestial bodies that cannot be analyzed by other means.
Emission spectrum of Hafnium
Absorption spectrum of Hafnium
Hafnium Chemical Properties: Hafnium Ionization Energies and electron affinity
The electron affinity of Hafnium is 0 kJ/mol.
| Valence | 4 |
| Electronegativity | 1.3 |
| ElectronAffinity | 0 kJ/mol |
Ionization Energy of Hafnium
Ionization energy is the amount of energy required to remove an electron from an atom or molecule.in chemistry, this energy is expresed in kilocalories per mole (kcal/mol) or kilojoules per mole (kJ/mol).
Refer to table below for Ionization energies of Hafnium
| Ionization energy number | Enthalpy - kJ/mol |
|---|---|
| 1st | 658.5 |
| 2nd | 1440 |
| 3rd | 2250 |
| 4th | 3216 |
Hafnium Physical Properties
Refer to below table for Hafnium Physical Properties
| Density | 13.31 g/cm3(when liquid at m.p density is $12 g/cm3) |
| Molar Volume | 13.44 cm3/mol |
Elastic Properties
| Young Modulus | 78 |
| Shear Modulus | 30 GPa |
| Bulk Modulus | 110 GPa |
| Poisson Ratio | 0.37 |
Hardness of Hafnium - Tests to Measure of Hardness of Element
| Mohs Hardness | 5.5 MPa |
| Vickers Hardness | 1760 MPa |
| Brinell Hardness | 1700 MPa |
Hafnium Electrical Properties
Electrical resistivity measures element's electrical resistance or how strongly it resists electric current.The SI unit of electrical resistivity is the ohm-metre (Ω⋅m). While Electrical conductivity is the reciprocal of electrical resistivity. It represents a element's ability to conduct electric current. The SI unit of electrical conductivity is siemens per metre (S/m).
Hafnium is a conductor of electricity. Refer to table below for the Electrical properties of Hafnium
| Electrical conductors | Conductor |
| Electrical Conductivity | 3300000 S/m |
| Resistivity | 3e-7 m Ω |
| Superconducting Point | 0.128 |
Hafnium Heat and Conduction Properties
| Thermal Conductivity | 23 W/(m K) |
| Thermal Expansion | 0.0000059 /K |
Hafnium Magnetic Properties
| Magnetic Type | Paramagnetic |
| Curie Point | - |
| Mass Magnetic Susceptibility | 5.3e-9 m3/kg |
| Molar Magnetic Susceptibility | 9.46e-10 m3/mol |
| Volume Magnetic Susceptibility | 0.0000705 |
Optical Properties of Hafnium
| Refractive Index | - |
Acoustic Properties of Hafnium
| Speed of Sound | 3010 m/s |
Hafnium Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Hafnium
| Melting Point | 2506 K(2232.85 °C, 4051.130 °F) |
| Boiling Point | 4876 K(4602.85 °C, 8317.130 °F) |
| Critical Temperature | - |
| Superconducting Point | 0.128 |
Enthalpies of Hafnium
| Heat of Fusion | 25.5 kJ/mol |
| Heat of Vaporization | 630 kJ/mol |
| Heat of Combustion | - |
Hafnium Isotopes - Nuclear Properties of Hafnium
Hafnium has 36 isotopes, with between 153 and 188 nucleons. Hafnium has 5 stable naturally occuring isotopes.
Isotopes of Hafnium - Naturally occurring stable Isotopes: 176Hf, 177Hf, 178Hf, 179Hf, 180Hf.
| Isotope | Z | N | Isotope Mass | % Abundance | T half | Decay Mode |
|---|---|---|---|---|---|---|
| 153Hf | 72 | 81 | 153 | Synthetic | ||
| 154Hf | 72 | 82 | 154 | Synthetic | ||
| 155Hf | 72 | 83 | 155 | Synthetic | ||
| 156Hf | 72 | 84 | 156 | Synthetic | ||
| 157Hf | 72 | 85 | 157 | Synthetic | ||
| 158Hf | 72 | 86 | 158 | Synthetic | ||
| 159Hf | 72 | 87 | 159 | Synthetic | ||
| 160Hf | 72 | 88 | 160 | Synthetic | ||
| 161Hf | 72 | 89 | 161 | Synthetic | ||
| 162Hf | 72 | 90 | 162 | Synthetic | ||
| 163Hf | 72 | 91 | 163 | Synthetic | ||
| 164Hf | 72 | 92 | 164 | Synthetic | ||
| 165Hf | 72 | 93 | 165 | Synthetic | ||
| 166Hf | 72 | 94 | 166 | Synthetic | ||
| 167Hf | 72 | 95 | 167 | Synthetic | ||
| 168Hf | 72 | 96 | 168 | Synthetic | ||
| 169Hf | 72 | 97 | 169 | Synthetic | ||
| 170Hf | 72 | 98 | 170 | Synthetic | ||
| 171Hf | 72 | 99 | 171 | Synthetic | ||
| 172Hf | 72 | 100 | 172 | Synthetic | ||
| 173Hf | 72 | 101 | 173 | Synthetic | ||
| 174Hf | 72 | 102 | 174 | 0.16% | Stable | N/A |
| 175Hf | 72 | 103 | 175 | Synthetic | ||
| 176Hf | 72 | 104 | 176 | 5.26% | Stable | N/A |
| 177Hf | 72 | 105 | 177 | 18.6% | Stable | N/A |
| 178Hf | 72 | 106 | 178 | 27.28% | Stable | |
| 179Hf | 72 | 107 | 179 | 13.62% | Stable | N/A |
| 180Hf | 72 | 108 | 180 | 35.08% | Stable | N/A |
| 181Hf | 72 | 109 | 181 | Synthetic | ||
| 182Hf | 72 | 110 | 182 | Synthetic | ||
| 183Hf | 72 | 111 | 183 | Synthetic | ||
| 184Hf | 72 | 112 | 184 | Synthetic | ||
| 185Hf | 72 | 113 | 185 | Synthetic | ||
| 186Hf | 72 | 114 | 186 | Synthetic | ||
| 187Hf | 72 | 115 | 187 | Synthetic | ||
| 188Hf | 72 | 116 | 188 | Synthetic |
Regulatory and Health - Health and Safety Parameters and Guidelines
The United States Department of Transportation (DOT) identifies hazard class of all dangerous elements/goods/commodities either by its class (or division) number or name. The DOT has divided these materials into nine different categories, known as Hazard Classes.
| DOT Numbers | 2545 |
| DOT Hazard Class | 4.2 |
NFPA 704 is a Standard System for the Identification of the Hazards of Materials for Emergency Response. NFPA is a standard maintained by the US based National Fire Protection Association.
The health (blue), flammability (red), and reactivity (yellow) rating all use a numbering scale ranging from 0 to 4. A value of zero means that the element poses no hazard; a rating of four indicates extreme danger.
| NFPA Fire Rating | N/A | N/A |
| NFPA Health Rating | N/A | N/A |
| NFPA Reactivity Rating | N/A | N/A |
| NFPA Hazards | N/A |
| Autoignition Point | - |
| Flashpoint | - |
Database Search
List of unique identifiers to search the element in various chemical registry databases
| Database | Identifier number |
|---|---|
| CAS Number - Chemical Abstracts Service (CAS) | CAS7440-58-6 |
| RTECS Number | RTECSMG4600000 |
| CID Number | CID23986 |
| Gmelin Number | - |
| NSC Number | - |
Compare Hafnium with other elements
Compare Hafnium with Group 4, Period 6 and Transition Metal elements of the periodic table.
Compare Hafnium with all Group 4 elements
Compare Hafnium with all Period 6 elements
Compare Hafnium with all Transition Metal elements
Frequently Asked Questions (FAQ)
Find the answers to the most frequently asked questions about Hafnium